A wireless local area network (WLAN) is widely applied to a home, an office, and another indoor/outdoor environment. In a high-density deployment scenario (for example, a stadium, where a height of an antenna above a ground is approximately 15 meters (m) to 50 m), there are many users per unit area, and a small-angle directional antenna needs to be used to reduce a coverage radius of a single access point device. A sidelobe suppression capability of the directional antenna determines a capability to suppress co-channel interference between adjacent access point devices in the high-density deployment scenario.